1. Field of the Invention.
This invention pertains to typewriter and teleprinter ribbon guidance mechanisms and structures, and to ribbon cartridges.
2. Description of the Prior Art.
With the advent of practical and widely used typewriters and teleprinters which have a printing device carriage-transported back and forth along a writing line, it became necessary to provide ribbon supply and take-up systems which also could be transported by the carriage in order to avoid ribbon advance during non-printing movements of the carriage and to obviate the use of special loop formers such as shown in my U.S. Pat. No. 3,534,847, and other contrivances to conserve or length-wise adjust the ribbon as in U.S. Pat. Nos. 2,609,077 and 3,726,381, or adjust a tape as in U.S. Pat. No. 3,236,353. In order to simplify ribbon threading, many of the present systems have taken the form of an easily installed ribbon supply and take-up cartridge or cassette which is also supported by the carriage. Unfortunately these carriage-supported systems have severe drawbacks. They add considerable weight to the carriage, require carriage-supported ribbon feeding and take-up devices which add additional weight and complexity to the carriage, and are limited in ribbon supply capacity due to weight and available space considerations. These drawbacks are eliminated by this invention.